What are the rulings for fasting one day and breaking fast one day, specifically regarding avoiding singling out Friday or Saturday for fasting, dealing with Mondays, Thursdays, and the White Days if they coincide with days of breaking fast, and how to act when visiting one's mother on Sunday if it is a fasting day?

There is no harm in singling out Friday or Saturday for fasting if it coincides with a customary day of fasting, such as for someone who fasts every other day, and does not intend thereby to specifically single out Friday or Saturday for fasting. However, if a customary day of fasting coincides with a day on which fasting is prohibited, such as Eid and the days of Tashreeq, then one must break their fast. In the case of visiting a mother who loves for you to eat at her home and would be saddened by your not eating, breaking your fast with her is better than fasting; because honoring parents and bringing joy to them takes precedence over supererogatory fasting.